How Does a Hydraulic Scissor Lift Work?

Hydraulic scissor lifts are an essential piece of equipment for any modern warehouse. Their ability to elevate individuals and items of massive weight by up to fifty feet make it possible to open your warehouse up to entire new avenues of vertical space. That new freedom can help you boost the efficiency and productivity of your operations, to say nothing of the fact that the same piece of equipment allows you to process items that were simply too heavy to handle before. If you've ever seen a hydraulic scissor lift at work, you may have wondered how such an unassuming piece of machinery can handle such incredible weights. The answer lies in the distinct parts of the lift and the way they work together.

Parts of a Hydraulic Scissor Lift Include:

Platform - The top of the lift table can, depending on the model, take on a variety of shapes, sizes and thicknesses. Lifts used solely for the transportation of product will often not feature a rail, while those that lift people must possess that safeguard to prevent those upon it from falling.

Base - Likewise, the dimensions of the base will vary by model. In addition to serving as the foundation of the lift, bases also provide a track for the rollers on the bottom of the scissor legs to travel upon. This guidance allows for a steady lift and descent bolstered by a base of tough, rigid metal (typically iron).

Scissor Legs - The legs stretch from the base to the platform, designed to allow the latter to rise as they contract and descend as they're spread. This is the portion of the lift to which the hydraulics are attached, and are technically the only part of the machine that moves.

Hydraulic Cylinders - Your unit may contain anywhere from one to four cylinders of hydraulic fluid - we'll go more into the specifics of their operation in just a moment.

Power Source - Though the cylinders serve as the heart of the lift, they're useless without something to power their operation. Their power is typically supplied by an electric motor but can also be provided by a high pressure, industrial air compressor. Depending on your unit, the power source will either feature a self-contained motor or a remote power pack.

Hydraulic Power in Scissor Lifts

If this is your first time reading about hydraulics, we recommend examining this guide to learn more about the basic principles. In the simplest terms, hydraulic scissor lifts operate by pushing liquid from one area to another. More specifically, the motor or air compressor forces hydraulic fluid into the associated cylinder, which causes that cylinder to be pushed outwards. That causes the scissor legs to be pushed apart, which in turn raises the platform. The level of fluid can be maintained by a check valve, which allows the operator to maintain the platform at a constant height.

The lowering of the platform is executed by the lift opening a down valve and allowing the hydraulic fluid back into its original container. That valve manages the flow of the fluid in order to prevent too rapid a descent, which can be potentially disastrous both for the operator and the load. Furthermore, that valve won't activate until its electric solenoid is activated, which prevents the sudden descent that would otherwise result from a power failure. A second valve - the flow control valve - handles the speed at which the platform descends by dictating the speed at which the fluid leaves the cylinder. These are non-adjustable and typically designed to provide a speed of descent identical to the speed of ascent.

Speed and Power of Hydraulic Scissor Lifts

Though all hydraulic scissor lifts operate in this manner, there is great variety in the pace and power with which they do so. As you might imagine, the speed at which the platform rises will be dependent on the weight upon it - that's because the pushback from that weight makes it more difficult for the engine to press the liquid against the cylinder with enough force to push it outward. If speed is a primary concern, you may consider ordering a unit with higher horsepower. Likewise, an increase in motor horsepower generally corresponds to an increase in lift capacity.

Keep in mind, however, that more horsepower also means a greater strain on the lift. Forcing the liquid through at a higher speed puts more pressure on all of the unit's mechanical components, which can lead to a shorter lifespan for your lift and an increase in maintenance costs. You might instead look into purchasing a unit with a high-voltage motor. Generally speaking, a 230 or 460-volt, 3-phase motor will provide twice the lift speed of that of a 110 volt, 1-phase motor.

Hydraulic Scissor Lifts for Your Warehouse

Hydraulic scissor lifts are nothing less than a modern marvel, an illustration of what can be accomplished when a principle as simple as hydraulics is harnessed and pushed to its fullest potential. That said, the technology is not flawless and not every model will be perfectly suited to the needs of your warehouse. Now that you've learned how hydraulic scissor lifts work and how the units can differ, we encourage you to browse our selection to find the model that's right for you. Need help in your search? Get in touch with one of our equipment experts for exceptional advice on hydraulic scissor lifts and on all the equipment we offer.